War Machine star Alan Ritchson says the film's most dangerous stunt was "pretty terrifying," as he ziplined over rapids without a blue screen: "There's just no way to fake that"

War Machine star Alan Ritchson says there was no blue screen involved during one of the film's most terrifying scenes.

Warning: mild spoilers for Netflix's War Machine below!

"That was a pretty rough week, but I was grateful to be doing it that way," Ritchson tells GamesRadar+. "It was pretty terrifying getting in that water, falling in, trying to stay, stay afloat. The zipline, all that... it was real, you know. There's just no way to fake that. If we did that on blue screen in a sound stage or something... which we were told we'd have to do [...] but you can't do that. You can't do a crossing over a class five rapid like that. But, we pulled it off..."

In the new Netflix movie, Alan Ritchson plays a U.S. Army Ranger known only as '81' who is given the impossible task of leading a team of hopeful trainees against an unknown (and seemingly unkillable) entity. In one particularly terrifying scene, 81 and his team need to find a way to hide from the titular War Machine... and end up crossing dangerous rapids with just a hook and some rope. Let's just say... it doesn't work out as smoothly as they'd hoped (and the danger feels so real, I doubt you'll be able to sit still while watching it).

Ritchson previously told GamesRadar+ that it was the most physically demanding role he'd ever taken on, even moreso than the stunt-heavy action series Reacher. Directed and co-written by Patrick Hughes, the cast includes Dennis Quaid, Stephan James, Jai Courtney, Esai Morales, Blake Richardson, Keiynan Lonsdale, and Daniel Webber.

"It requires shooting films the way we shot War Machine in that it's all in camera and out in real-world locations," Hughes added. It's worth noting that the bombs dropped in the film were indeed real, as is that freaky alien machine, which is the result of practical FX (which makes it all the more terrifying).

"It requires heavy lifting, all the work in pre production just to be able to get us the access, to be able to pull this off, because there's just so much of a machine behind making a movie... just to end up there on the day with an actor jumping in grade five rapids with all the safety and and the insanity that it took. It just takes a lot of legwork in pre-production, but it pays off for me personally. I mean, the easy out would be like, 'Oh, let's just do it on VFX and green screen.'"

War Machine is streaming on Netflix now. For more, check out our picks for the best sci-fi movies of all time.